Lennox MPB012S4S Service Manual

121
Error Code: P3
Description: Outdoorcompressorcurrentoverloadsensed
General Note: Iftheoutdoorcurrentexceedsthecurrentlimitvalue,theLEDwilldisplaythefailure.
Current protection of compressor.
Checkwhethertheinputcurrentofthepower
supplyshouldnotexceedmorethan12Afor18KBTU
units.
For30K,18.5A.
For36K,itis23A.
Yes
CheckwhethertherefrigerantsystemisOK.
Checkwhethertheoutdoorambienttemperature
ishigherthan50°Cor122F
No
Replaceoutdoormainboard.
No
Stoptheunit.
Yes
Checkifoutdoorunithasproperventilation.
No
Correct poor ventilation to outdoor unit.
Yes
Checkoutdoorcoils.Outdoorcoilsshouldbeclean
and free of any debris.
Clean outdoor coils.
Yes
No
Judge5:Therefrigerantpipeisblocked.
Recoverrefrigerantandremoverestriction(s).
Performpropervacuumprocedures,then
restart system.
Yes
No
Replaceoutdoormainboard,andcheckwhetherthe
system can run normally.
No
Replacetheelectriccontrolbox.
Problem Solved.
Yes
Yes

Lennox MPB012S4S Specifications

General

Brand	Lennox
Model	MPB012S4S
Category	Air Conditioner
Language	English